The archive stores four kilometres of shelving in a closed concrete core. Around it, a single helical stair climbs 31 metres and joins every public floor, so visitors move through the collection rather than past it.

The stair is made of 168 identical precast treads, hung from a steel inner ring. A glass balustrade keeps the well open, and a roof light at the top sends daylight down the full height of the building.

Climate

The heavy core keeps the collection at a stable 18 °C with almost no mechanical cooling. The reading rooms on the perimeter are naturally ventilated for most of the year.